Heat exchanger element obtained by casting, and method for preparing polystyrene patterns for casting

ABSTRACT

A heat exchanger element obtained by sand casting, having a modular structure and comprising a right head module, a left head module, and at least one optional intermediate module.

The invention relates to a heat exchanger element obtained by sandcasting and to a method for preparing polystyrene patterns for saidcasting.

BACKGROUND OF THE INVENTION

A casting process, particularly for casting aluminum alloy elements, isknown which provides for the preparation of a polystyrene pattern whichreplicates exactly the shape of the casting and is embedded in sand;during the pouring of the molten metal, the metal replaces thepolystyrene, which evaporates, and the desired element is thus obtained.

This casting process is known as “lost foam”.

The polystyrene pattern is obtained by connecting together by gluingcomponent sectors, each of which is provided by means of anappropriately provided apparatus which, due to a certain inherentcomplexity, has a high cost.

It is also known that there are heat exchangers, used particularly inboilers for generating hot water, which are studied so that they aremanufactured by composing identical elements in a number which isproportional to the thermal power to be obtained; a certain range ofcapacities to be marketed is thus provided, but such range isnecessarily limited.

SUMMARY OF THE INVENTION

The aim of the present invention is to provide a heat exchanger elementwhich can be obtained with the lost foam casting process and to alsoprovide a method for preparing polystyrene patterns for performing suchcasting, which allow to provide, at a reduced cost, a very wide range ofavailable thermal powers.

This aim is achieved by a heat exchanger element according to theinvention, characterized in that it has a modular structure whichcomprises a right head module, a left head module, and at least oneoptional intermediate module.

A method for preparing polystyrene patterns for sand castingdifferentiated elements of heat exchangers of the type described aboveis characterized in that it comprises:

-   -   a first step for obtaining three sectors: a first sector for        forming the right head module, a second sector for forming the        left head module, and a third sector for forming an intermediate        module;    -   a second step for assembling the complete pattern by connecting        together by gluing the two sectors that form the right and left        heads, with the optional interposition of a number of sectors        for forming an intermediate module, selected as a function of        the thermal power to be obtained from said exchanger element.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will becomebetter apparent from the description of some embodiments thereof,illustrated by way of nonlimiting examples in the accompanying drawings,wherein:

FIG. 1 is a perspective view of an exchanger element according to theinvention;

FIG. 2 is a front view of the exchanger element shown in FIG. 1;

FIG. 3 is a front view of the three polystyrene sectors for formingpatterns according to the invention;

FIGS. 4, 5 and 6 are views of exchanger elements according to otherembodiments according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the FIGS. 1 and 2, the reference numeral 1 generallydesignates a heat exchanger element which has a modular composition,since it is composed of a right head module 2, three identicalintermediate modules 3, 4 and 5, and a left head module 6.

The polystyrene pattern for sand casting the element 1 is obtained byconnecting together by gluing the two sectors 7 and 8 designed to formrespectively the right head 2 and the left head 6 and at least one andpreferably three sectors such as the one designated by the referencenumeral 9, which are designed to form the three intermediate modules 3,4 and 5.

By joining selectively different numbers of sectors such as the onesshown in FIG. 3, it is possible to obtain polystyrene patterns forcasting a very wide range of differentiated exchanger elements: thus,FIG. 4 illustrates an exchanger element 10 which has a minimal thermalpower, since it comprises only the two heads 11 and 12 obtained frompolystyrene sectors 7 and 8.

FIG. 5 is a view of an element 13 which has a higher thermal power,since it comprises, in addition to the two heads 14, 15, also theintermediate module 16 obtained from a polystyrene sector 9.

FIG. 6 is a view of element 17, which has an even higher thermal power,but not as high as the element 1, since it comprises, in addition to thetwo heads 18 and 19, two intermediate modules 20 and 21.

It is therefore evident that it is possible to obtain a very wide rangeof exchanger elements having differentiated thermal power, and it isimportant to note that this possibility is achieved in terms of greateconomy because the factor that most affects the entire process,constituted by the cost of the apparatuses designed to provide thepolystyrene patterns, is minimized: the number of these apparatuses isin fact reduced, regardless of the thermal power of the element to beobtained, to only the three fixtures designed to obtain the threesectors shown in FIG. 3.

The described invention is susceptible of numerous modifications andvariations, all of which are within the scope of the appended claims;all the details may further be replaced with other technicallyequivalent elements.

The disclosures in Italian Patent Application no. MN2006A000076, fromwhich this application claims priority, are incorporated herein byreference.

What is claimed is:
 1. A heat exchanger element obtained by sandcasting, comprising a modular structure which comprises a right headmodule, a left head module, and at least one intermediate module.
 2. Amethod for preparing polystyrene patterns for sand castingdifferentiated elements of exchangers according to claim 1, comprising:a first step for obtaining three sectors: a first sector for forming theright head module, a second sector for forming the left head module, anda third sector for forming the intermediate module; a second step forassembling the complete pattern by connecting together by gluing the twosectors that form the right and left heads, with interposition of anumber of sectors for forming the intermediate module, selected as afunction of the thermal power to be obtained from said exchangerelement.